Single-piece female electric contact terminal having reinforced transition part

ABSTRACT

The invention relates to a female electrical contact terminal obtained from a single plate of electrically conductive metal: including a rear part making possible a crimped connection with an electrical wire, a front part including a cage  4   a  consisting of a bottom, a top, two sides, at least one strip ensuring a contact with a complementary male contact terminal, a transition part linking the front part with the rear part, an extension leg at least traversing the transition zone.

FIELD OF THE INVENTION AND PRIOR ART

The invention relates to a female electrical contact terminal made inone piece from a stamped and bent sheet metal, intended to receive acomplementary male contact terminal.

The invention finds applications in the field of electrical andelectronic connectors and, in particular, in the field of connectorsdevoted to the automobile industry.

In the field of connectors, there is an effort to make connectors thatare increasingly less expensive. To this end, there is an effort todesign connectors that necessitate, on the one hand, the smallest amountof material possible and, on the other hand, the simplest fabricationpossible. In order to meet these demands, it is known to produce femaleor male connectors or contact terminals in one piece from a single plateof sheet metal or of electrically conductive metal, referred to as metalfoil, which is stamped and bent to form the desired connector.

In particular, female electrical contact terminals of the cage type areproduced. Such a contact terminal consists of a rear part in which anelectrical wire is fixed by crimping to connect it with anotherelectrical wire fixed in a complementary male contact terminal. Thisfemale contact terminal also consists of a front part in the form of acage, which is intended to receive the male contact terminal, and atransition part linking the front part with the rear part.

Such a female contact terminal is described in the patent application EPA 0 959,531. The cage of this contact terminal is made from a metalplate in which a bottom part, two sides (or lateral walls) and a toppart are stamped and formed. The top part is made of two parts placedside to side. A tab is stamped and bent in the side to form the contactstrip by means of which electrical contact is established between thefemale terminal and the complementary male terminal. In this femalecontact terminal, each element is made “as a single wall”; that is, eachside of the contact terminal consists of only a single thickness ofmetal. In particular, the sides of the cage each consist of a singlewall provided with an opening and an electrical contact strip placedacross this opening. The top part is made of two parts positioned sideby side. Owing to its being made as a single wall, the cage of thiscontact terminal affords a significant risk of crushing, particularlywhen the contact terminal is handled during production. Moreover, thisconstruction as a single wall makes the contact terminal very fragile innarrow places and, in particular, in the region of intersection ofcutting lines. In fact, owing to the stamping, forming, and bending ofthe sheet metal of small thickness, the intersections of the cuttinglines can shear off and/or tear off under the effect of a lateralmechanical force exerted on a wall or parallel to this wall. This riskis particularly high in the thin zones, such as the transition zonebetween the rear part of the crimping of the electrical wire and thecage of the front part of the contact terminal.

These drawbacks become particularly important when, for economicreasons, manufacturers reduce the thickness of the sheet metal with theaim of reducing the costs of fabricating contacts.

To solve this problem, the applicant has created a female electricalcontact terminal of the cage type in which the sides of the cage areextended in the part near to the transition zone. Such a contactterminal is described in the patent application filed in the name of theapplicant under the number EP A 0 812,034.

The contact terminal described in this patent application comprises arear part in which is crimped an electrical wire, a front part in theform of a cage intended to receive a complementary male connector, and atransition part linking the front part and the rear part. The cage ofthis contact terminal comprises a bottom, a top formed of two partsplaced side by side, and two sides, each provided with an opening and abend forming a shoulder for the male contact when the latter isintroduced into the female contact terminal.

In this female contact terminal, each side extends up to the beginningof the transition part by way of a branch in the shape of a square. Thisextension of the sides of the cage makes it possible to create areinforcement between the transition part and the cage itself, whichrigidifies this zone situated in the region of the line of intersectionbetween the cage and the transition zone, which is referred to as ajunction trapezoid. In other words, the intersection of the cuttinglines of the cage and the beginning of the transition part (in contrastto the end of the transition part, which is contiguous to the partbehind the crimping) is reinforced by these branches, which extend thesides of the cage.

However, this reinforcement does not make it possible to reinforce thetransition part itself. On the contrary, the end of the transition part,situated in the vicinity of the rear part, is made increasingly morefragile as the beginning of the transition part is reinforced. Thus, inthe case of a mechanical force, the contact terminal that has just beendescribed has little risk of shearing off or tearing off at thebeginning of the transition zone, because it is reinforced there; bycontrast, this rigidity introduces a fragility into the remainder of thetransition part and particularly in the vicinity of the rear part.

The contact terminal described in the application EP A 0 812,034comprises, in addition, two tabs stamped in the extension of the partsforming the top and bent into the interior of the cage in order to formcontact tabs. Each of these tabs constitutes a second thickness of thelateral wall, which rigidifies the sides of the cage.

However, the creation of these contact strips from the parts forming thetop necessitates the existence of a notch in each of the parts formingthe top. The top of this contact terminal is thereby made fragile,particularly in the front part of the top, that is, the part introducedfirst into the male contact. In the event of poor manipulation of thefemale and male terminals, the top of the female terminal can becrushed.

DISCLOSURE OF THE INVENTION

The invention has the very object of remedying the drawbacks ofelectrical contact terminals described above. To this end, the inventionproposes a female electrical contact terminal made of one piece, inwhich at least one of the parts forming the top of the contact cageextends as a leg traversing the entire transition part. In addition, thesides of the cage are double-walled, the contact strip forming thesecond thickness of each side.

More precisely, the invention relates to a female electrical contactterminal that is obtained from a single plate of electrically conductivemetal comprising:

a rear part that permits a crimped connection with an electrical wire,

a front part consisting of a cage 4 a comprising a bottom, a top, twosides,

at least one strip ensuring a contact with a complementary male contactterminal,

a transition part linking the front part with the rear part,

characterized in that the top has at least one extension leg traversingthe transition zone.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 represents the female electrical contact terminal in accordancewith the invention before the electrical wire has been crimped.

FIG. 2 represents a stamped sheet metal, intended to be bent for formingthe contact terminal of FIG. 1.

FIG. 3 represents the stamped sheet metal of FIG. 2, partially bent inorder to form the cage of the contact terminal of the invention.

FIG. 4 represents the stamped sheet metal of FIG. 2, totally bent inorder to form the cage of the contact terminal of the invention.

DETAILED DESCRIPTION OF EMBODIMENT OF THE INVENTION

FIG. 1 represents a profile view from above of a female electricalcontact terminal in accordance with the invention. In FIG. 1, thecontact terminal, viewed from above, is represented as being ready to becrimped around an electrically conductive wire 1.

The female contact terminal of the invention has dimensions and an outerform identical to that of female contact terminals of the prior art.Thus, it can be inserted into a classical male contact terminal, knownto the person skilled in the art. The male contact terminalcomplementary to the female contact terminal of the invention willtherefore not be described here.

The female contact terminal of the invention comprises a rear part 2, afront part 4, and a transition part 3 linking the front part 4 with therear part 2.

The rear part 2 receives an electrical wire 1 intended to be connectedto another electrical wire, crimped in a male contact terminalcomplementary to the female contact terminal of the invention. This rearpart 2 comprises a bottom 23 as well as two lateral walls 21 and 22 ofcomplementary shape, which form crimp pieces. These walls 21 and 22 arerepresented as being opened in FIG. 1, that is, as being in the positionin which they are found after bending of the sheet metal forming thecontact terminal, but before crimping of the electrical wire 1. Thesewalls 21 and 22 are bent back and crimped around the insulator of theelectrical wire 1 in order to hold it in fixed position in the contactterminal. One thus says that the electrical wire 1 is crimped in thecontact terminal.

The rear part 2 comprises two other walls 31 and 32, forming crimppieces for the conductive part of the wire 1.

The front part 4 of the contact terminal comprises a cage 4 a and ajunction zone 4 b, referred to as a junction trapezoid, situated betweenthe cage 4 a and the transition part 3. The cage 4 a comprises a topformed from two parts 41 and 42, assembled together to form anessentially planar surface. In a preferred embodiment of the invention,the two parts 41 and 42 fit one into the other, thus rigidifying the topof the cage 4 a. For example, the part 42 of the top can have aprojecting part that forms a tenon and the part 41 of the top can have anotch that forms a mortise, which receives the tenon of the part 42.

As represented in FIG. 1, the part 41 of the top is extended by anextension leg 46, which traverses the entire transition part 3. In theembodiment represented in FIG. 1, the extension leg 46 ends at the rearof the transition part in the vicinity of the rear part 2 of the contactterminal. In another embodiment, the extension leg 46 traverses totallythe transition part 3 and ends in the rear part 2. In this case, it canbe positioned between the crimp pieces 31 and 32 of the conductive partof the wire 1.

In the embodiment of FIG. 1, only the part 41 of the top extends intothe rear part 2. The part 42 of the top is terminated by a tab 47 in thejunction trapezoid 4 b at the beginning of the transition part 3. Thisjunction trapezoid 4 b constitutes the junction zone between the cage 4a and the transition part 3 of the contact terminal. It is formed, onthe one hand, by the bottom of the front part 4 and, on the other hand,by the two top parts 41 and 42. It is thus double-walled, which makes itpossible to rigidify this zone of the contact terminal.

In a variant of the invention, each part 41 and 42 of the top of thecage 4 a comprises an extension leg 46. The two extension legs are thuspreferably symmetrical with respect to each other and are of the samelength.

The rear part 2 comprises a bottom 33 and two lateral walls 31 and 32.These walls 31 and 32 are represented as being open in FIG. 1, that is,not bent back toward the bottom 33, so as to show the extension leg 46that traverses the transition part. When the sheet metal is entirelyformed, these walls 31 and 32 are bent back toward the bottom 33 and thewall 31 surrounds the extension leg 46 of the part 41 of the top as wellas the stripped conducting strands of the wire or cable 1. In this case,where each part 41 and 42 of the top has an extension leg, each wall 31and 32 then surrounds one of the extension legs.

FIG. 2 represents a sheet metal or plate of sheet metal or of anelectrically conductive metal, which is stamped so as to be bent forforming a female contact terminal in accordance with the invention.Visible in FIG. 2, in particular, are the stampings made in the sheetmetal for forming the front part of the contact terminal. It is to benoted that the transition part and the rear part of the contact terminalare identical to those of the connector described in the application EPA 0 812,034. The stampings of the sheet metal for making this transitionpart and this rear part are identical to those shown in the prior art;their description is therefore included in this text by incorporation ofreference.

The stamped sheet metal thus comprises a bottom 51, sides 50 and 50′,and two top parts 41 and 42. Represented by dot-dash lines for a betterunderstanding of the invention are the places where the sheet metal willbe bent at the time the contact terminal is formed.

The bottom 51 has a rectangular shape, slightly cut out in its partintended for forming the front part of the contact terminal. In order tosimplify the figure, the bottom 51 has been represented solely in itspart intended for forming the front part of the contact terminal. Thisbottom 51 comprises a single stamping, in front, for making thereinforcement tab 52. This tab 52, the width of which is approximatelythree times greater than its length, will be bent back during thebending of the sheet metal, at an angle of 15 to 20 degrees toward theinterior of the cage 4 a in order to create a reinforcement at the edgeof the contact terminal and to facilitate the insertion of the malecontact terminal when the male contact terminal and the female contactterminal are inserted into each other.

Located on each side of the bottom 51 is a side 43 or 43′. The two sides43 and 43′ are identical to each other. As a result, only the side 43will be described here. This side 43 has an opening 44, intended toreceive a locking pin of the terminal in a socket of a connection boxreceiving this terminal.

During the stamping of the opening 44, exclusively three sides of theopening can be stamped, the rear side of the opening, that is, the sidenearest to the rear tab 45 is not stamped. The part of the sheet metalbent back in the interior of the opening can then be used forpretensioning the contact strip 45 after bending toward the axis of thereceiving cage of a contact pin or for constituting a stop for thisstrip, limiting its deformation in the case when a pin of too great across section is introduced or in the case when a pin is introduced atan angle. This stop can be made by bending back the stamped part of thesheet metal, in one or more bends, on the interior of the cage towardthe rear of the cage. This stop constitutes a safety feature when themale pin is inserted into the female terminal.

The side 43 contains, in addition, a first tab 45, referred to as a reartab. This rear tab 45 is stamped in the sheet metal between the opening44 and the rear of the contact terminal. During the bending of the sheetmetal, the rear tab 45 is bent toward the interior of the cage 4 a, fromthe rear toward the front, at an angle of approximately 180 degrees.This tab 45 forms a contact strip of the contact terminal of theinvention. It also forms a double wall of the side 43. In addition, thisrear tab 45 is placed, in the interior of the cage 4 a, along theopening 44.

Such an embodiment of the contact strip, stamped and formed in the side43 of the contact terminal, makes it possible to obtain a contact stripthat is narrower than in the prior art but more rigid, because itconstitutes the double wall of the side.

For a better electrical contact, the tab 45 can be bent back when it isformed, in such a way as to form a shoulder 53 of contact with thecomplementary pin.

The side 43 contains a second tab 50, referred to as a front tab,situated on the other side of the orifice 44 in relation to the rear tab45. When the sheet metal is formed, this front tab 50 is bent toward theinterior of the cage 4 a from the front toward the rear at an angleappreciably less than 180 degrees—for example, 160 degrees. This fronttab 50 has a length that is less than that of the rear tab 45, being onthe order of half thereof. The front tab 50 is bent on top of the reartab 45 in such a way that the end of the rear tab 45 is a supportagainst the front tab 50. The front tab 50 ensures a flexible support ofthe contact strip formed by the tab 45 in order to afford a precisevalue of the gap between the strips 45 and 45′ in the region of thezones of contact with the complementary pin, in order to pretension thestrips, and to guide the pin during its insertion.

The ends of the tabs 50 and 45 can be stamped at a right angle, that is,perpendicularly to the surface of said tabs, or else at a bevel in orderto adjust the overlap of these two tabs.

The side 43′ is identical to the side 43. It comprises the same elementsas the side 43, namely, the opening 44′, the rear tab 45′, and the fronttab 50′, the bends and roles of which are identical to those describedfor the side 43. The invention is applicable to a contact provided witha single strip 45.

Each side 43 and 43′ is contiguous to a top part 41 or 42. Moreprecisely, in FIG. 2, the side 43 is contiguous to the top part 42 andthe side 43′ is contiguous to the top part 41. As explained above, afterthe sheet metal is folded, the parts 41 and 42 are placed side by sideand assembled to form the top of the front part 4 of the female contactterminal.

In a preferred embodiment of the invention, the parts 41 and 42 havecomplementary shapes, which make it possible for one to fit into theother in order to rigidify the top. For example, the free side (oppositeto the side contiguous to the side wall) of one of the parts of the topis stamped to form a tenon and the free part of the other part of thetop is stamped to form a mortise. The free parts of the two parts of thetop can also be stamped to form zigzags that are complementary to eachother.

In the example of FIG. 2, the free side of the part of the top 41contains a stamping forming a mortise 48 and the free part of the partof the top 42 contains a projection forming a tenon 49 that fits intothe mortise 48 during the bending of the sheet metal.

In the embodiment of FIG. 2, the top part 41 contains an extension leg46, which, after bending of the sheet metal, is bent back toward thebottom 51 of the front part. More precisely, during the bending of thesheet metal, the extension leg 46 can be bent a first time at thejunction between the cage 4 a and the junction trapezoid 4 b and thenbent a second time at the junction trapezoid 4 b and the transition part3. After this second bending, the extension leg 46 is situated along thebottom 33 of the transition part 3.

In an embodiment of the invention, the extension leg 46 can extend up tothe interior of the rear part 2 and be received in the crimping zone ofthe conductive wire.

The intercalary zone 54 of the sheet metal situated between the mortise48 and the extension leg 46 has essentially the shape of a right-angledtriangle that is terminated by the extension leg, with a straight partthat is parallel to the bottom 51 and an angled part that allows thiszone 54 to be lodged in the junction trapezoid 4 b.

The part of the top 42 is terminated by an intercalary zone 47 that issymmetrical to the intercalary zone 54.

As explained above, the top part 42 can also consist of an extensionleg, which is symmetrical to the extension leg 46 of the part 41. Thisextension leg can have the same characteristics as those of theextension leg 46.

FIG. 3 shows the contact terminal of the invention during forming of thesheet metal. In FIG. 3, the contact terminal has been represented inprofile in a view rotated by 90° in relation to the view of FIG. 1. Thebottom 51 of the front part 4 is thus not visible in this FIG. 3. Bycontrast, this figure shows quite well the interior of the cage 4 a.Thus, this figure shows the side 43′ of the contact terminal of theinvention with its opening 44′ and its rear tab 45′ and front tab 50′bent back. This FIG. 3 also shows the top part 41, bent at a right anglein relation to the side 43′, with its intercalary zone 54 and its end 55bent toward the interior of the cage 4 a.

This FIG. 3 also shows the other side of the front part 4 in the courseof bending. Seen here is the rear tab 45 bent back toward the front witha bend forming a shoulder 53, the front tab 50 bent back on top of therear tab 45, and the intercalary zone 47 bent in order to enter thejunction trapezoid.

In this FIG. 3, the top part 42 has not yet been bent toward the otherpart of the top 41. This bending is the final bending to be carried outin order for the front part 4 to be formed.

FIG. 4 represents a side view, in profile, of the front part of thecontact terminal of the invention. This figure shows the contactterminal when the sheet metal is entirely formed. Seen here is the side43 with its opening 44, traversing which is visible the contact strip 45supported by the front tab 50. This figure also shows the inclination ofthe ends 55 and 52, respectively, of the top 41/42 and of the bottom 51as well as the inclination of the intercalary zones 54 and 47 of theparts 41 and 42 of the top. Also visible in this FIG. 4 is the junctiontrapezoid 4 b formed in the extension of the bottom 51 of the front part4 and the intercalary zones placed in this trapezoid 4 b.

The contact terminal that has just been described has the advantage ofbeing able to be produced in a sheet metal of dimensions equal to orless than those sheet metals of the prior art, while being rigidified bydouble walls and the extension of the top augmenting the section of thetransition zone as well as the section of current passage when at leastone extension leg is taken up in the crimping zone for the conductivewire. In fact, in the invention, the initial sheet metal (before beingstamped) has a relatively compact form with a length equal to the lengthof the final contact terminal and a width equal to twice the dimensionsfor one side and the bottom of said contact terminal.

In addition, the stampings made in the sheet metal produce littlematerial that is unused and thus is lost or needs to be recycled. Thereinforcements, such as the extension leg or the double walls of thesides, are created integrally in the sheet metal without the addition ofmaterial. In particular, the extension leg, which constitutes the doublewall of the transition zone, is made in a part of the sheet metal that,in the prior art, was not used.

1. A female electrical contact terminal obtained from a single plate ofelectrically conductive metal comprising: a rear part making possible acrimped connection with an electrical wire, a front part consisting of acage 4 a comprising a bottom, a top, two sides, at least one stripensuring a contact with a complementary male contact terminal, atransition part linking the front part with the rear part, characterizedin that the top has at least one extension leg traversing the transitionzone.
 2. The contact terminal according to claim 1, furthercharacterized in that the top has two assembled parts, one of said partscontaining at least the extension leg.
 3. The contact terminal accordingto claim 2, further characterized in that each part of the top containsan extension leg.
 4. The contact terminal according to of claim 2,further characterized in that the extension leg traverses the transitionpart and enters the rear part.
 5. The contact terminal according toclaim 2 to 4, further characterized in that the two parts of the top fitinto each other.
 6. The contact terminal according to claim 5, furthercharacterized in that one of the parts of the top forms a tenon and theother part of the top forms a mortise.
 7. The contact terminal accordingto claim 1, further characterized in that the sides each contain a firsttab, bent back toward the interior of the cage from the rear toward thefront.
 8. The contact terminal according to claim 7, furthercharacterized in that the sides each contain a second tab bent backtoward the interior of the cage 4 a from the front toward the back ontop of the first tab.
 9. The contact terminal according to claim 1,further characterized in that at least one extension leg extends betweenthe crimp pieces of the electrical wire and is crimped with the wire.